Student-Teacher Ratio Calculator

Because they measure different things. Current Ratio divides Total Students by Effective Staff, which includes Teacher Aides weighted by their Aide Equivalency percentage. Avg Class Size divides Total Students by Total Teachers only, with no aide contribution at all -- so a school with substantial aide staffing will show a lower Current Ratio than its Avg Class Size might suggest.

No. Current Ratio is calculated purely from Total Students and Effective Staff (Total Teachers plus weighted Teacher Aides) -- it never references Target Ratio at all. Target Ratio only feeds into two other outputs, Additional Teachers Needed and Meets Target?, both of which compare your actual staffing against that policy benchmark.

It depends entirely on Aide Equivalency (%). At 50% equivalency, 5 aides count as 2.5 additional FTE toward Effective Staff -- meaningful, but half the impact of 5 more full teachers. At a lower equivalency percentage, the same aide headcount moves Current Ratio much less, since Effective Staff only grows by aides times that percentage.

They isolate the effect of a single hiring decision, since staffing conversations are usually about one position at a time rather than a large restructuring. Comparing Current Ratio to Ratio if +1 Teacher shows exactly how much one additional hire would improve the ratio, which is often the concrete number a budget request needs. Ratio if -1 Teacher shows "—" instead of a number for a small staff (for example, one teacher and no aides) where losing one more position would leave zero or negative effective staff -- there is no meaningful ratio for a classroom with no staff at all, and showing 0:1 there would misleadingly read as a perfect ratio.